Damage Mechanism And Protection Technology For Fractured Carbonate Reservoirs In Shunbei Block

Shunbei Block is located in the territory of Shaya County.Xinjiang Province.It is a key exploration and development block of the Northwest Bureau of Sinopec.It has a total exploration area of 3,126km2.and has completed drilling of dozens of wells,all of which have shown rich oil and gas production and have a remarkable economy.And social benefits.The block develops the Ordovician carbonate marine reservoir,which is about 7,500 meters deep.Reservoir fractures and micro-fractures develop.During the actual drilling and completion,the solid particles of the drilling fluid are easy to invade the reservoir,blocking the fracture and reducing The seepage ability of the fracture caused damage to the reservoir and seriously affected oil and gas production.Based on the drilling design and geological survey of the Ordovician reservoirs in the North Block,the reservoir cores and cuttings of Wells Shunbei 1-3 and Well Shunbei 2 were first collected,and the mineral composition and microstructure of the reservoir rocks were collected.Based on the analysis of the matrix properties,the five-sensitivity and stress sensitivity evaluation of the Ordovician reservoir was completed,the reservoir damage mechanism was revealed,and the corresponding preventive measures were proposed:for the reservoir damage mechanism,the indoor optimization Acid-soluble fiber,calcium carbonate(coarse grain),and calcium carbonate(fine grain)are three kinds of high acid-soluble shielding temporary plugging agents,and their acid-soluble filtration rate exceeds 90%,and they can achieve acidification back row.Based on on-site drilling fluid treatment materials,three types of highly acid-soluble temporary plugging agents were used as the core treatment agent to complete the optimization of the drilling fluid system in the Ordovician reservoir section.The recovery value of the permeability of the reservoir protection drilling fluid system is over 85%,water loss is low 5ml,high temperature and high pressure loss is low 10ml,instructed the construction of 1-10H reservoir section in North Jiangsu,and the fluid loss of the drilling fluid was maintained at about 4mL.No leakage or kick occurred.Downhole is complicated and has achieved good reservoir protection.